PROBLEM OF ROAD SAFETY

Press, Volume LXXI, Issue 21411, 1 March 1935, Page 8

PROBLEM OF ROAD SAFETY

FACTORS TO BE g CONSIDERED IMPACT FIGURES COMPARED The lowest toll of road accidents for 13 years was reached in London recently; yet there are few who will infer that this is the beginning of any great or lasting improvement in road safety, says the motoring correspondent of the "Morning It is too well known that, in spite of many palliatives, some of them highly ingenious and a few fairly successful, no comprehensive grip of the situation has yet been obtained, and no integral road safety plan devised. Definition of responsibility is probably the source of more bickering about road safety than anything else. The pedestrian says the motorist ought to look out while the motorist says the pedestrian ought to look out; the lorry driver blames the cyclist and the cyclist the lorry driver. Is there any method of grading responsibility? There is; by the standard of momentum.

I have hoard motorists praising the skill of drivers for having "saved the lives of hundreds of foolish pedestrians every day." Such an attitude argues forgctfuliiess of the fact that a head-on collision between a pedestrian and a motorist, both going at equal speed, will, in the vast majority of cases, .injure the pedestrian severely and leave the motorist unhurt. A great deal of anti-motoring legislation is probably the result of the unconscious realisation of the nakedness of the pedestrian; his complete lack of. armour. The pedestrian requires protection by law because he is not mechanically protected. A Common Failing Pedestrians, it is admitted, do foolish things. But so do motorists. Every human being, especially the very old and the very young, is apt to do .something "without thinking." But if the motorist does something "without thinking" he may be unhurt, while the pedestrian is likely to be seriously hurt. It is for the protection of people who do things "without thinking"— that is, for everybody at some time in their lives—that road safety plans must be devised, and the protection must be graded in inverse ratio to the mechanical protection of the person concerned.

The pedestrian is most in need of protection. The pedal cyclist comes next, the motor-cyclist next, the small private car driver next, and the enormous lorry-cum-trailer driver last. Unless he drives over the edge of a cliff, or tries conclusions with a train, the large lorry driver will be fairly safe. In a collision, the other man is likely to get the worst of it. Ten tons trundling along at 20 miles an hour can do.more damage if they get out of hand than one ton travelling at 100 miles an hour. Spged, then, is indeed the essential factor in road safety; but speed only in relation to circumstances, one of the circumstances being the total weight of the vehicle. Let me quote some figures given by Mr A. Lampert, of the ArmstrongSaurer Company. If a small 5001b trolley hits a wall at live miles an hour and is stopped by the wall in one two-hundredth of a second, the force of the impact will be 10.02 tons. The trolley is going at only five miles an hour, yet its momentum is such that a person standing against the wall would be dealt with as effectively as by a firing squad. Let now the vehicle be a 12-ton lorry, the speed 30 miles an hour, and the slopping period one-thousandth of a second. The force of the impact upon the wall is then 16,300 tons. "The result is sufficiently impressive," writes Mr Lampert—and I want to place every possible emphasis upon his words—"to make one inclined to ask the driver of a 'heavy,' 'Have you ever realised this?'" Meaning- of Momentum One useful step towards road safety is to force upon drivers of all vehicles a realisation of the meaning of momentum. It is not speed alone that determines the damage a vehicle can do if it gets out of hand, but speed by weight. The weights of private cars run from about 14cwt to about 45cwt. The Austin Seven chassis weighs 12cwt, and the big Mercedes, complete with body, weighs 45cwt. The unladen weight of commercial vehicles ranges from vans, which come within the private car limits, to vehicles weighing, unladen, more than 140cwt.

Here, then, is n standard which should help to determine road respon- ; sibility. Given an equal speed, the driver of the heavier vehicle has the greater responsibility. It sounds obvious enough. Yet I am sorry to say that I see almost daily on the roads instances of heavy vehicles, especially motor coaches, being driven without their drivers showing any appreciation of the extra responsibility which rests upon them. An excellent lesson in momentum is occasionally to be learnt in garages with sloping floors. A "garagist" opens the door of a car, leans inside it, and takes off the handbrake. The car moves forward, very slowly indeed; but if the "garagist" has let go of the brake and cannot get at it again at once, he can sturggle with his feet as much as he likes and he will not be able to stop the car until—as usually happens—the open door meets some obstruction and there is a rending of hinge screws, and considerable damage to coachwork is done. If hinges can be torn off when the car is trickling along, the pedestrian stands small chance of avoiding serious injury if he is run down when the car is moving under power. Speed and Circumstance The motoring view that slow speeds in the wrong place are.more dangerous than high speeds in the right place is, therefore, justified, and the speed limit method of control is illogical. The only speed limit that could influence road safety would be an infinitely variable speed limit, varying according to the thousand factors upon which the determination of a safe speed at any given instant depends. Such an infinitely variable speed limit is impracticable. It remains, therefore, for the drivers to be taught that their speed should never be influenced by a competitive urge, that motor-coaches, for instance, should not attempt to "race" light cars; but that they should be influenced by the type of vehicle, its weight, and the road and traffic conditions: The weight of the vehicle partly determines the force it can exert in an accident; but the driver cannot vary the weight. Consequently he must himself apply—for it is impossible for the law to apply it—that infinitely variable speed limit that will enable him to retain adequate control at all times.